Facial Soft-tissue Mobility: Baseline Dynamics of Patients with Unilateral Facial Paralysis

The aims of this observational study were 2-fold: (1) To demonstrate a method and measures to quantify impaired facial soft-tissue movements in patients with facial paralysis; and (2) To quantify the differences in magnitude and velocity of facial soft-tissue movements between patients with facial paralysis and control participants.

The study sample that addressed both aims consisted of 20 adults with acute, unilateral, flaccid facial paralysis who presented at the onset of their paralysis, and a control group of 20 healthy adults. Dynamic 3D facial movement data were collected from each participant during 11 facial animations. To compare the movements between the patients and control participants, dynamic modeling comparisons of mean facial movements were computed as well as plots of movement vectors for each animation, in addition, measures of maximum displacement, movement velocity, and asymmetry were computed.

Dynamic 3D modeling of critical facial landmarks provided precise profiles of zone-specific asymmetries and customized reporting that highlighted areas of importance for individual patients. The dynamic 3D movement data confirmed that the nonparalyzed side of patients' faces had abnormal directional movements. As expected, the controls had significantly higher excursive facial movements during all animations except during gentle eye closure, which was greater for the patients and the controls had significantly greater movement velocity than the patients. The patients had significantly greater asymmetry for all the animations, and the hierarchy of the asymmetry was such that maximum smile > lip purse > grimace > cheek puff.

Dynamic 3D modeling appeared to be an effective tool to provide precise profiles of zone-specific asymmetries and customized reports for patients with facial paralysis.